Invasive Breast Cancer

Invasive breast cancer occurs when cancer cells from inside the milk ducts or lobules break out into nearby breast tissue.

Cancer cells can travel from the breast to other parts of the body through the blood stream or the lymphatic system. They may travel early in the process when a tumor is small or later when a tumor is large.

If breast cancer spreads, the lymph nodes in the underarm area (the axillary lymph nodes) are the first place it's likely to go.

Metastatic breast cancer

Metastatic breast cancer (also called stage IV or advanced breast cancer) is invasive breast cancer that has spread beyond the breast and axillary lymph nodes to other organs in the body (most often the bones, lungs, liver or brain).

Metastatic breast cancer is not a specific type of breast cancer, but rather the most advanced stage of breast cancer.

Less common invasive breast cancers

Inflammatory breast cancer is a rare, but aggressive form of locally advanced breast cancer. It’s called inflammatory breast cancer because the main warning signs are swelling (inflammation) and redness of the breast.

With inflammatory breast cancer, warning signs tend to arise within weeks or months (with other breast cancers, signs may not occur for years).

Metaplastic breast cancer is a rare cancer that can be hard to diagnose because the tumor cells can look very different from the tumor cells of more common breast cancers. Metaplastic tumors tend to be larger and have a higher tumor grade than more common breast cancers.

Prognosis for invasive breast cancer

The chances for survival after invasive breast cancer depend on each person’s diagnosis and treatment.

For example, people diagnosed with early breast cancer have a better prognosis than those diagnosed with more advanced breast cancer.